Electrical seaming apparatus



Janv4, 1949. N. v. cHRls'rENsEN Erm. 2,458,059

ELECTRICAL SEAMING APPARATUS 5 Sheets-Shed. 1

Filed l Sept. 15, 1944 NNN NNN

Jan 4, 1949. N. v. cHRls'TENsz-:N r-:rAL 2,453,059

ELECTRICAL SEAMINQ' APPARATUS 5 Sheets-Sheet 2 Filed Sept..` 15, 1944 NSN Mh.

Jan. 4, 1949. N. v. cHRlsTENsEN ETAL 2,458,059

ELECTRICAL SEMING APPARATUS Filed sept. 15. 1944 ywwwwww @M- ATURZE'Y Jan. 4, 1949.

Filed Sept. 15, 1944 N. V. CHRISTENSEN ETAL ELECTRICAL sEAMING APPARATUS 5 Sheets-Sheet 4 Jan. 4, 1949. N. v. cHRlsTENsEN Erm. 2,458,059

ELECTRICAL SEAMING APPARATUS Filed sept. 15, 1944 5 sheets-sheet :s

Wa N Afro/YM? Patented Jan. 4, 1949 yELECTRICAL SEAMING APPARATUS Norman V. Christensen, Chicago, Ill., Hamid J. Le Vesconte, Glendale, Calif., and Albert M.

Schweda, Chicago, Ill.,

assignors to Union Special Machine Company, Chicago, Iii., a corporation of Illinois Application September 15, 1944, Serial No. 554,306

9 Claims. (Cl. 154-42.)

This invention relates to apparatus for electrically seaming or uniting two or more parts, at

least one of which becomes plastic upon being high frequency electric current to obtain an eifective and adequate union between two or more parts that are to be Joined together.

This invention has for its primary object the provision of apparatus that'is adapted to be advantageously employed in obtaining an effective and efficient bonding or uniting between two or more layers of material at leastone of which is thermoplastic and dielectric in character, shaped to form a tubular article, by the use of an ultrahigh frequency electriccurrent.

It is another object of this invention to provide apparatus of the above type in which the various parts are so constructed and arranged as not to obstruct the vision of the operator or interfere with the handling and manipulating of the material to be formed into a tubular article. A feature of the invention, toward this end, is the provision of a free ended, cylinder-like work supporting arm around which the work may be formed into tubular shape as the seeming operation is performed.

This invention has for another object the provision of apparatus of the character mentioned above in which certain work advancing devices may be operated either intermittently or continuously, as desired.

A further object of this invention is to provide apparatus of the type indicated which is simple in design, sturdy in construction, substantially free of vibration, reasonable in initial cost, substantially trouble-free in operation, and inexpensive to operate and maintain.

In accordance with our instant invention, we provide a frame that may consist of a base, hav-n ing a portion extending upwardly and outwardly thereof, to form an overhang which terminates in an upper horizontal member that houses a main rotary shaft. The horizontal member of the frame has at one end a depending member, from the lower end of which there extends a tubular, laterally projecting horizontal work supv porting arm. The work supporting arm isv free at its outer end and so constructed and arranged 2 as to provide clear space to the sides of and beneath the same. The arm is further so disposed with respect Vto the upper horizontal 'member that a vertical plane, longitudinal of the arm, forms an acute angle with a corresponding vertical plane, longitudinal of the upper horizontal member. Projecting laterally of one end of the upper horizontal member is a housing which supports a shaft that is adapted to cooperate with the main shaft and to impart rotation to one wheel or rotary electrode of this invention. A similar wheel, constituting the second rotary electrode of the invention, is carried proximate the free end of the work supporting arm, and extends slightly thereabove. Both wheels are preferably rotatable on substantially horizontal and parallel axes in substantially the same vertical plane, and are so disposed as to have their peripheral surfaces in opposition. The peripheral surfaces of the wheels are preferably spaced apart at all times. The lower Wheel is disposed on a fixed axis while the upper wheel is on a vertically movable axis. Yielding means is provided to normally urge the upper wheel in a vertical direction toward the lower wheel. Provision is made to move the upper wheel in an opposite vertical direction against the action of the yielding means. This arrangement permits the wheels to accommodate themselves to varying thicknesses in the parts being joined together by the apparatus of our invention and allows the operator to increase the spacing between the wheels as may be found desirable and at his will. Appropriate connections, including shafts and gearing, are provided between the main shaft and both wheels to impart rotation in opposite directions to the wheels, simultaneously and preferably at the same angular velocity. The wheels may be rotated either continuously or intermittently, as will be more fully discussed hereinafter.

Each of the wheels or rotary electrodes is in electrical communication with a suitable high frequency electric current generator by means of a transmission line, which is preferably made of a length equal to substantially one-quarter of the wave length at the operating frequency, in order that maximum voltage may be applied to the parts to be united. The rotary electrodes have at least their peripheral portions formed of desirable electrically conductive material and are of sufilcient mass to conduct away from the outer surfaces of the parts being united the heat developed therein, in order that only the contacting regions of the parts to be united are caused to become tacky and are thereby made to adhere 3 to each other in a manner that will be readily understood by those skilled in the art from the detailed disclosure appearing hereinafter.

By virtue of the cooperative relative relationship'of the various elements entering into the present invention, clear space is provided below the work supporting arm to permit the tubular article to be formed around the arm. to permit the operators hand and arm to move freely between the work supporting arm and the other portions of the frame structure, and to bring various external operating parts of the apparatus within the field ot vision of the operator.

The above enumerated objects and features, as well as additional objects and features, together with the advantages obtainable by the practice of the present invention, will be readily apparent to persons skilled in the art by reference to the following detailed description and the accompanying drawings which respectively describe and illustrate two embodiments of the invention. and wherein Figure 1 is a side elevational view of a machine having one embodiment of the invention, a part of the machine being shown in vertical crosssection and certain parts being omitted;

Figure 2 is a top plan view of the apparatus of Figure 1, with parts shown in transverse crosssection and with certain parts broken away and other parts removed;

Figure 3 is a rear end elevation of said embodiment of the invention, `some parts being broken away and shown in vertical cross-section. Certain parts depicted in Figures 1 and 2 are omitted in Figure 3, while certain other parts, not shown in the other figures, are illustrated in Figure 3;

Figure 4 is a view partly in front elevation and partly in vertical cross-section along line 4-4 of Figure 1;

Figure 5 is a vertical sectional view of a portion oi' the machine, taken along line 5--5 of Figure 2;

Figure 6 is a top plan view of the work supporting arm of Figure 5, some parts being shown in horizontal cross-section and certain parts being removed:

Figure '7 is a transverse vertical section through the work supporting arm, taken along line l-l of Figure 5;

Figure 8 is a transverse vertical section through the work supporting arm, taken along line 8-8 of Figure 5;

Figure 9 is a view similar to Figure 8 and illustrates a modied form of work supporting arm;

Figure 10 is a side elevation of the upper wheel or rotary electrode and associated elements;

Figure 11 is a view in vertical section through the upper wheel, taken along line iI-Ii of Figure 10;

Figure 12 is a horizontal sectional view taken along the broken line I2-i2y of Figure 10;

Figures 13 and 14 are a side elevation and a top plan view, respectively. of a bracket or connector element associated with the upper electrode;

Figures 15 and 16 are side and end elevational views, respectively, of a guard member associated with the upper electrode;

Figures 17 and 18 are an elevation and a bottom plan view, respectively, of a bevel gear employed in the illustrative embodiment of the invention;

Figure 19 is a view similar to Figure 2 and illustrates a second embodiment of the invention; and

Figure 20 is a rear end elevational view of the upper portion of the second embodiment of the 4 invention and corresponds with part of Figure 3 of the first embodiment.

Referring more particularly to the drawings wherein like reference characters are used to denote corresponding parts throughout the several views, reference numeral 25 generally indicates a metallic frame including a base 26, a bracket 2l extending upwardly and outwardly of the base and terminating in a hollow horizontal upper member 28, which is provided with readily removable top cover plates 28 and 30 that are malntained in place by screws 8i and 32, respectively, and a removable front end cover plate 33 that is attached to the frame by screws such as that indicated by numeral 84 in Figure 1. A depending tubular member 35 may be cast integral with one end of upper member 28, and carries at its lower end a tubular laterally projecting horizontal work supporting arm 36. Arm 38 is maintained in desired angular position with respect to depending member by means of one or more aligning pins 81 and screws 88, as indicated in Figure 5. A vertical plane, extending longitudinally of the axis of upper horizontal member 28, would cut the same along a line AA, while a similar vertical plane, extending longitudinally of the axis of work supporting arm 88, would intersect the first vertical plane and would out the work supporting arm along the line 5-5 oi' Figure 2. These planes form an acute angle C. Arm 38 is provided with a horizontally slidable cover plate 38 and a verticaliy slidable cover plate 40 (Fig. 1) to provide ready access to the interior thereof. Arm 36 is also provided with a plurality of top cover plates including plate 4| and plate 42, the former being adapted to be retained in the illustrated position by a spring pressed latch, generally denoted by numeral 43. Extending laterally of upper horizontal member 28, adjacent its left end (Fig. 2) is a housing 44. This may be secured in any suitable way (not shown) to the member 28 of the main frame.

A main shaft 45, extending through the rear end oi' upper member 28, is rotatably supported in a plurality of bearing sleeves 46, 4l, 48 and 49, which are suitably mounted within upper member 28. Thebearing surfaces of the above-mentioned sleeves may be lubricated in any desired manner known to the art. For example, a packing material 50, that is saturated with an appropriate lubricant, is contained within an opening formed in supporting wall 5l, with the result that the lubricant flows through a passage 52 in sleeve 4l to shaft 45. Collars 53 and 54 embrace shaft 45 and are affixed thereto by means of set screws 55 and 5B, respectively, to restrain shaft 45 from objectionable axial movement during operation. Shaft 45 carries a pair of bevel gears of like size, namely, bevel gear 51, that is secured lto the shaft intermediate sleeve 46 and collar 53 by a set screw 58, and a bevel gear 59, that is attached to the inner end of shaft 45 by a set screw 6U. As will be observed in Figure 1, sleeve 48 is positioned in a vertical leg 5| or an L-bracket 82 that has its horizontal leg l'connected to the under surface of partitions 64 and 65, integral with the frame, by screws 65 and 6l, respectively (Fig. 4). Horizontal leg B3 is provided with a bearing sleeve 58 through which a vertical shaft 69 extends. A bevel gear 'l0 that mates with bevel gear 59 is affixed to the upper end of shaft 68 by a set screw 1i within the space between the ends of partitions 54 and 65. A collar 12, that is attached to shaft 68 by a set screw 13 immediately below bearing 88, prevents upward vertical movement of shaft 88 during operation.

Asis shown in Figures and 7, shaft 88 has a second bevel gear 14 attached thereto by' a set screw 15. The lower end of shaft 88 is journaled in a sleeve 18, which is provided in a horizontal leg 11 of a second L-bracket 18, having a-vertical leg 18 that is provided with a horizontal bearing sleeve 88. Leg 11 of L-bracket 18 rests on the bottom of work supporting arm 38 and is rigidly attached thereto by a plurality of screws 8|.

A shaft 82 extends longitudinally within tubular work supporting arm 38 and is `iournalerl proximate its opposite ends in sleeve 88 and an opening in a vertical wall 83 at theend of the cast portion of the work arm. Carried at one end of and rotatable with shaft 82 is a bevel gear 84 that is preferably of the same size as, and meshes with, bevel gear 18. A collar 85 is mounted on shaft 82 by a set screw 88 to cooperate with bevel gear 84 in preventing undesirable axial movement of said shaft. A bevel gear 81 is connected to the' opposite end of shaft 82, beyond the wall 83, by means of a set screw 88.

Integral with end plate 42, which is secured by screws 4'2u(Fig. 2) lto the wall 83, is a depending lug 88 that has a horizontally disposed sleeve 88 formed in its lower portion (Figs. 6 and 8). A pin 8|, having a head 82, is mounted in sleeve 88 and carries a collar 83, secured by a set screw 84, at its free end. Rotatably mounted on pinl 8 I, intermediate sleeve 88 and head 82, is a bevel gear 85 that meshes with bevel gear 81. As will be noted from an inspection of Figure 8, the axes of bevel gears 81 and 85 are coplanar, but at right angles to each other. A wheel. 88, constituting one of the rotary electrodes of our invention, is concentric and rotatable with bevel gear 85 and should .preferably be composed of a material having good electrical conductive properties. The periphery oi wheel 98 extends through and slightly above a slot 81 in cover plate 42. A housing member 88, having a cylindrical wall portion complementary to the cover plate 42, and a vertical end wall, serves to enclose the gears 81 and 85 and` related parts. It may be slotted, if desired, to permit the wheel 88 to extend through the same, as indicated in Figure 8. Any suitable means, such as screws, may be employed for attaching the housing member to the work arm casting.

The modification of the invention illustrated in Figure 9 differs from that depicted in Figure 8 primarily in the configuration of the top of the end cover plates. Cover plate 42 of Figure 9 has one side curved, as indicated at 88, while the opposite side carries a lateral extension or lip |88 to provide a wider working surface to the right of wheel 88 than that shown in Figure 8.

Turning next to housing 44 for a detailed discussion of the apparatus contained therein, it will be noted that the same is provided with an in=l wardly extending lug |8| that has integral therewith a sleeve-like extension |82. A shaft |83, rotatable in bearing |82, has its axis in the horizontal plane of, but at right angles to, the axis of main shaft 48. A bevel gear |84, that meshes with bevel gear 51, is attached by a set screw |85 to one end of shaft |83, While a second bevel gear |88 is attached by a set screw |81 to the opposite end of shaft |83. A vertical shaft |88 extends through housing 4 4 and is provided with a longitudinally extending slot or key-way |88 along a substantial portion of its length. A bevel gear I I8, that is illustrated in detail in Figures 17 and 18, is provided with a central bore III to receive shaft |88 and a key ||2 adapted to register with slot |88 in the shaft. Gear ||8 is formed with an annular groove ||3. A bracket element ||4 (Fig. 1) has a vertical portion ||5 and a horizontally extending yoke |I8 that cooperates with `annular groove ||3 to rotatably support bevel gear ||8. Element ||4 is secured to housing 44 by a screw or bolt II1 that passes through a vertical slot ||8 in portion ||5. It will be observed that element ||4 is thereby adjustable vertically to accurately position bevel gear ||8 in proper mesh with gear |88. By virtue of the arrangement just described, bevel gear ||8 and shaft |88 are simultaneously rotated upon rotation of bevel gear |88. Bevel gear ||8 is restrained from vertical movement by element II4, but shaft |88 is vertically movable with respect lto bevel gear H8 through the co-action of key I|2 and slot |88.

In Figures 13 and 14 there is illustrated a bracket or connector |28 consisting of arms |2| and |22 that are provided with parallel bores |23 and |24, respectively, and a third arm |25 that is provided with a bore |28 having its axis normal to that of bore |24 and substantially but not quite normal to the plane of the axes of bores |28 and |28. As is shown in Figures 10 and 11shaft |88 extends through bore |28 of arm |22 and carries a bevel gear |21, attached by set screw |28, at its lower end. A collar |28 embraces shaft |88 immediately above arm |22 vand is secured to the shaft by means of a set -screw |38. A pin |3i, having a head |32, ex-

tends through and is rotatably supported in bore |28 of arm |25. A bevel gear |38 that meshes with bevel gear |21 is carried by pin |39 intermediate head |82 and arm |25. The free end of pin |3| has a collar |34 connected thereto by a set screw |35. A wheel, generally denoted by reference numeral |38, carried by and rotatable with bevel gear |33, and constituting the other rotary electrode of the apparatus of our invention, includes a main body portion 31 that is made of a suitable electrical insulating material and a rim of good electrical conductivity consisting of an annular ring |38 and an inwardly larranged in spaced relation to the peripheral surface of wheel |36 as to protect the operators hand from coming in contact with said wheel. A somewhat similar guard |42 is located in the region of bevel gear |33.

A tubular rod |45, vertically slidable in bushings |48and |41 (Fig. i3) extends through and beyond the top and bottom of housing 48. The lower end of rod |45 is suitably locked in bore |23 of arm |2| of connector |28. A collar or similar means |48 adjustably limits downward movement of rod |45. A member |48, embracing rod |45 and having a lateral extension |58, is secured to the rod by set screws I5| (Figs. 1 and 2).

Wheels or rotary electrodes 88 and |38 are disposed on substantially horizontal and parallel axes that are located in a substantially vertical mesma heretofore described. is such that wheels 86 and are rotated simultaneously in opposite directions and at the same angular velocity.

The apparatus of this invention includes a mechanism for normally and yieldingiy urging rod |40. and consequently connector |20, shaft |08, and wheel |86 downwardly to its lowermost position. A mechanism that may be advantageously employed for this purpose is illustrated in Figures 8 and 20, wherein the same is generally denoted by numeral |62. This includes an upwardly projecting bolt |63 that is pivotally supported at its lower end by a horizontal pin |54 and that extends through a spring assembly consisting of a plurality of leaf springs |56, |58 and |61. A knurled adjusting nut |56 is in threaded engagement with the upper end of bolt |58 and bears against the upper surface of leaf spring |61 to tension the springs to any extent desired. A pair of vertical lugs |58 are formed integral with bracket 21, and each lug carries a laterally projecting arm |60 that is secured to the lug by a screw |8|. A cross-bar |62 is secured to the outer end of each arm |80 by means of a screw or bolt |88 and may be used to support auxiliary attachments (not shown). One end of lower leaf spring V|60 is connected to cross-bar |62 by means of `the left-hand bolt |60, while the opposite end of this spring is coupled to rod |46 by a swivel cap |64. It will be apparent that the mechanism just described tends to yieldingly-urge rod |45 in a vertically downward direction, and to the position shown in Figure 3.

Reference is now had to an arrangement of apparatus for simultaneously moving rod |45, connector |20, shaft |08 and wheel |36 vertically upward against the action of spring mechanism |52. A preferred arrangement of this character is illustrated in Figures 2 and 3, and comprises a bell crank |65 pivotally supported by o. pin |86 that extends laterally and to the side of the lefthand arm |50 (Fig. 2). A link |61 is pivotally connected at its oppositeends to bell crank |65 and to an arm |68 through the medium of screws |68 and |10, respectively. Arm |68 is clamped to a horizontal rock-shaft |1| extending through and supported in a vertical wall of housing 44, and having an arm |12 formed integral therewith, said arm being adapted to bear against the under surface of lateral extension |50. A downward pull may be imparted to the free end oi' bell crank |65 by means of an appropriate cable or the like (not shown) that is connected to a foot treadle or a knee operated member (also not shown). Such a downward pull rocks crank |66 in a counter-clockwise direction, as viewed in Figure 3, thereby moving link |61 toward the left and imparting an increment of counter-clockwise rotation to arm |68. Since arm |68 is clamped to rock-shaft |1|, the latter will also be rotated in a counter-clockwise direction, with the result that the free end of arm |12 will move lateral extension |50 of member |48, rod |45, and the associated apparatus upwardly against the action of mechanism |52.

A bracket |14, cast integral with and extending laterally of frame bracket 21, supports a variable speed driving unit |15 that serves as the prime mover of the machine. Driving unit |16 preferably consists of a suitable electric motor |18, that is supplied with electrical energy from a convenient source (not shown) by a conductor cable |11I and a conventional type of speed controller |18 in the transmission from the motor. Speed controller |18 is provided with a rotatable knob |10 for manually adjusting the same, which knob also operates an indicator pointer |60 that rides in a slot III. Mounted on the speed controller parallel to slot |0| isa plate |02 having graduations or like indicia |48 that serve as visual aids in the adjustment oi' the speed of driving unit |16. A drive shaft |84 extends beyond one end of the driving'unit for connection in a suitable manner with the main shaft of the machine.

Reference is next had to the embodiment of the invention illustrated in Figures 1, 2 and 3 for a full understanding of one suitable type of connection between drive shaft |84 of the driving unit and main shaft 45 in upper horizontal member 28, for imparting simultaneous and intermittent rotation to rotary electrodes 88 and lll. This apparatus includes a plate |85 secured to the exposed end of drive shaft |84 and rotatable therewith. Plate |85 is grooved at |88 to adjustably receive the square head of a ball stud |01 whose axis is parallel with, but eccentric, to the axis ci drive shaft |84. The extent of eccentricity of the axis of ball stud |81, with. respect to the axis of drive shaft |84, is indicated by the distance between lines DD and EE (Fig. 3) which represent horizontal planes along the respective axes. This eccentricity may be varied by adjusting the ball stud along the groove |88 by means of a screw |81a. A rod |88, adjustable in length, is pivotally coupled at opposite ends 'to ball stud |81 and to a second bali stud |88 that is carried at the free end of an arm |88. As will he observed from an examination of the drawings, rotation of plate |85 results in oscillation of arm which is connected to a clutch mechanism |8| that is in part carried hy main shaft 45. Clutch mechanism iti may be of any desired type known to the art, such that illustrated and described in Hacirlander Potent 2,043,749. It is sumclent to point out that the movements irnparted to arm |80 in one direction serve to actuate a member of clutch mechanism 10| which is secured to shaft 45 in a manner to intermittentl'y rotate said shaft and 'the associated shafts and bevel gears so as to correspondingly drive rotary electrodes 88 and |36 simultaneously and intermittently in opposite directions. Movements of the arm |88 in the opposite direction are idle and means are provided in the clutch mechanism for preventing reverse movement of shaft 45 at this time.

The second embodiment of the invention pertains to apparatus cooperating with drive shaft |64 of drivingr unit |15 to impart continuous rotation to main shaft 45 and thence to rotary electrodes 86 and |36. The means for obtaining this continuous rotation is illustrated in Figures 19 and 20 and comprises a drive pulley |82 connected to the end of shaft |84 and rotatable therewith. Rotation of drive pulley |82 is transmitted through the medium of a. belt |83 to a driven pulley |84 that is fastened at the upper end of a vertical shaft |85. Shaft |85 is journaled in vertically spaced bearings |86 and |98a carried by projections from an end closure member |81 of the part 28 of the frame. Concentric with shaft |85 and intermediate bearings |86 and |86a is a worm gear |88 which is keyed to a Collar |88 that is attached to shaft |86 by a set screw 200 to the end that the worm gear rotates with this shaft as the driving unit is operated. Worm gear |88 mates with a worm wheel 20| that is screw 202.

assaose affixed to the outer-end of main/shaft 33 by a set Referring next to Figures 1 and 3, we`have i1- lustrated therein a table, or the like 233, for supporting the frame 23. and means for supplying a suitable high frequency electric current to rotary lelectrodes 93 and |33. This means includes an ultra-high frequency oscillation generator 233 of any suitable construction that is connected to an appropriate source of electrical supply l(not shown) by a conductor cable203 and that is suspended below table 233 by a pair of brackets 231 and 233. Concentric lines; consisting of an outer tubular'conductor 233 and an inner conductor 2N that emerge from generator 203 at 2l pass through an opening 2I2 in table 233 vand transmit the high frequency current-to the wheels or rotary electrodes 33 and |33 in a manner about tobeexplained. l f

- Conductor 203 is attached to frame 23 by means of an electrically conductive bracket 2|3 surrounding the conductor and a screw 2M by which the bracket is fastened to the frame; hence the conductor is in electrical communication with rotary electrode 83 which is grounded to the frame. Inner conductor 2|0 is in series electrical communication with an L-shaped spring strip conductor 2|! and ring |33 of rotary electrode |33 with which the free end of the spring strip is resiliently engaged. Inner conductor 2li) and spring strip conductor` 2|! are attached to an insulator 2|3 by a screwv or terminal post 2|-1.

Insulator 2|3 is attached to housing 33 in any convenient manner, such as by means of screws 2|3 (Fig. 2). A small neon lamp 2|3 is'in electrical communication with spring strip conductor 2 I 3 and has its other terminal grounded, thereby serving to visually indicate the presence of the high frequency current in the circuit.

As was indicated earlier herein, the means for transmitting the high frequency current from oscillation generator 203 to rotary electrodes 33 and |33 should preferably be of a length equal to substantially one-quarter of the wave length at the operating frequency, in order that maximum voltage may be applied to the parts that are to be bonded together. The frequency of the current supplied by oscillation generator 203, and the electrical power input'to rotary electrodes 33 and |33 are factors which may be readily determinedby persons skilled in the art, and will de pend at least in part upon the character of the parts to be joined together and the nature of the bond to be obtained. At least one of the parts to be united shouldbe thermoplastic in character or a thermoplastic strip shouldV be inserted be tween these parts. The high frequency current creates an electric field in the dielectric parts to be united in the region of their contact with the rotary electrodes, and the heat generated in these parts by this electric field causes the thermo plastic part or parts to become sticky or tacky, whereby they are joined together. I'he rotary lelectrodes should have good heat conducting properties to dissipate as much as possible the heat developed at the surfaces of 4the material directly engaged by the electrodes and thus prevent any tendency to stick to the electrodes. The

peripheral surfaces of the rotary electrodes may be smooth, as illustrated,'or may be roughened, in order to provide better` traction for the work as it is fed between and beyond the electrodes.

l lo j I ployed in connection with the modified construction of Figures 19 and-20 for delivering a high frequency current to the electrodes thereof.

The operation of the machine is believed to be .i

clear but a brief rsum will be given.' Alternating electric current as ordinarily available,V at

say 110 voltsand 60 cycles.` will be delivered through cables |11 and 233 to the driving unit ill'and the high frequency oscillatcrfrespectively. The operator will be seated in front of the right-hand end of the work supporting arm 33 (Figs. 1 and 2) and will be facing along this arm. The work, which may be flat sheet material to be formed into a `tube or series of tubes, is folded by the operator aroundthe work arm in advance'of the wheels 33 and |33 and the edges are overlapped to any extent desired. Upper roller |33 is raised slightly, by rocking the bell crank llthrough treadle control or the like, sumciently to enable insertion of the forward end of the work between the rollers. Motor |13 is then set in operation or, if desired, a clutch may be engaged to couple the motor with the main shaft 33 of the machine. Depending upon the form of the invention adopted, the shaft 33 will be rotated either continuously or intermittently in a series of short increments of rotation. This rotation of the shaft 43 will be transmitted to the wheels 33 and |33 which will thus serve to advance the work along and then oi! of the work arm. At the same time the'high frequency current will be passed between the wheels or electrodes thereby producing a seam in the form of a line of adhesion between the overlapped portions of the work. If the operation of shaft 33 is intermittent, as in the first embodiment, a sort of stitch effect may be produced in the uniting of the edges of the work. 'A continuous sexies of spots will be created at which a more effective bond is provided between the layers of the work due to the prolonged time interval allowed between the successive movements of the work. When a particular seaming operation has been completed the current to the motor and to the oscillator is preferably cut on. l

From the foregoing it is believed that the construction, operation and advantages obtainable by the practice of our instant invention will be readily understood by persons skilled in the art. It is to be borne in mind. however, that various changes in the apparatus, herein illustrated and described, may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

We claim:

ers of material, at least one of which is thermoplastic, a lower member comprising a tubular lIt will be y'understood that the same arrange- 3 "ment as described .inthe foregoing may be emarm having a slot formed in the upper portion thereof, an vupper member secured to the lowermember and disposed above and spaced from the arm, a wheel having its major portion within the peripheral confines of the arm and a marginal portion in registration with the slot and projecting thereabove, a wheel carried by the upper member in cooperative relation to the first-mentioned wheel, said wheels being arranged for rotation on substantially horizontal and parallel axes lying in a substantially vertical plane that is generally normal to the arm and cooperating to feed material placed therebetween. at least the peripheral portion of each wheel being electrically conductive, and means adapted tovbe connected to asource of high frequency current for creating a high frequency electric field between the peripheral portions of the wheels, said means including said wheels.

2.1n apparatus for bonding a plurality of layers of material. at least one of which is thermoplastic. a lower member comprising a tubular arm having a slot formed in the upper portion thereof. an upper member secured to the lower member and disposed above and spaced from the arm, a wheel carried proximate one end of the arm, said wheel having its major portion within the peripheral confines of the arm and a marginal portion in registration with the slot and projecting slightly beyond the exterior surface of the arm, a wheel carried by the upper member in cooperative relation to the firstmentioned wheel, said wheels being arranged for rotation on substantially horizontal and parallel axes that lie in a substantially vertical plane and cooperating to feed material placed therebetween relative to and toward the other end of the arm, at least the peripheral portion of each wheel being electrically conductive, and means adapted to be connected to a source of high frequency current for creating a high frequency electric eld between the peripheral portions of the wheels, said means including said wheels.

3. In apparatus for bonding. a plurality of layers of material, at least one oi' which is thermoplastic, a lower member comprising a. tubular arm having a slot formed in the upper portion thereof, an upper member secured to the lower member and disposed above and spaced from the arm. a wheel having its major portion within the peripheral confines of the arm and a marginal portion in registration with the slot and pro-` Jecting thereabove, a wheel carried by the upper member in cooperative relation to the firstmentioned wheel, said wheels being arranged for rotation on substantially horizontal and parallel axes lying in a substantially vertical plane that is generally normal to the arm and with their peripheral surfaces in opposing relation, means for urging one wheel in a substantially vertical directiontoward the other wheel, means for moving said one wheel in a reverse direction against the action of the first-named means, means for rotating the wheels in opposite directions. said wheels :being arranged to feed material placed therebetween, and means adapted to be connected to a source of high frequency current for creating a high frequency electric field between the peripheral portions of the wheels, said means including said wheels.

4. In apparatus for bonding a plurality of layers of material, at least one of which is thermoplastic, a lower member comprising a tubular arm having a slot formed in the upper portion thereof, an upper member secured to the lower member and disposed above and spaced from the arm, a wheel having its major portion within the peripheral confines of the arm and a marginal portion in registration with the slot and projecting thereabove, a wheel carried by the upper member in cooperative relation to the firstmentioned wheel, said wheels being arranged for rotation on substantially horizontal and parallel axes lying in a substantially vertical plane that is generally normal to the arm, at least the peripheral portion of each wheel being electrically conductive, means for rotating the wheels simultaneously and intermittently in opposite directions, said wheels being arranged to feed material placed therebetween, and means adapted to be connected to a source of high frequency current for creating a high frequency electric field between the peripheral portions of the wheels when the wheels are separated, said means including said wheels.

5. Inl apparatus for bonding a plurality of 'layers of material, at least one of which is therginal portion in registration with the slot and projecting thereabove, a wheel carried by the upper member in cooperative relation to the firstmentioned wheel, said wheels being arranged for rotation on substantially horizontal and parallel axes lying in a substantially vertical plane that is generally normal to the arm and with their peripheral surfaces in opposing relation, means for urging one wheel in a substantially vertical direction toward the other wheel, means for moving said one Wheel in a reverse direction against the action of the first-named means, means for rotating the wheels simultaneously and intermittently in opposite directions, said wheels being arranged to feed materialplaced therebetween, and means adapted to be connected to a source of high frequency current for creating a high frequency electric field between the peripheral portions of the wheels, said means including said wheels.

6. In apparatus for bonding a plurality of layers of material. at least one of which is thermoplastic, a base, a bracket extending upwardly and outwardly of the base, a depending member carried by the upper part of'the bracket, a tubular arm having a slot formed therein secured to one end of the depending member and projecting laterally thereof, an upper member ailixed to the bracket and disposed above the arm in spaced relation thereto, a wheel carried by the arm proximate the free end thereof, said wheel having its major portion within the peripheral confines of the arm and a marginal portion in registration with the slot and pro- ,iecting slightly beyond the-exterior surface of the arm, a wheel carried by the upper member above the first-named wheel, said wheels being arranged for rotation on substantially horizontal and parallel axes in a substantially vertical plane generally normal to the arm and with their peripheral surfaces in opposing relation, at least the peripheral portion of each wheel being electrically conductive, means for normally urging one wheel in a substantially vertical direction toward the other wheel, means for moving said one wheel in the opposite direction against the action of the first-named means, means for rotating the wheels simultaneously and intermittently in opposite directions, said wheels being arranged to feed material placed therebetween, and means adapted to -be connected to a source of high frequency current for creating a high frequency electric iield between the peripheral portions of the wheels, said means including said wheels. i

7. In apparatus for bonding a plurality of layers of material, thermoplastic. a lower member comprising a tubular arm having a slotfformed in the upper portion thereof, an upper member secured to the lower member and disposed above and spaced from the arm, a wheel having its maior portion within the peripheral confines of the arm and a marginal portion in registration with the slot at least one of which is and projecting thereabove, a wheel carried by' -the wheels are separated, said means including,

said wheels.

8. In apparatus for bonding a plurality of layers of materials, at least one of which is thermoplastic. a lower member comprising a tubular arm having a slot formed in the upper poftion thereof, an upper member secured to the lower member and disposed above and spaced from the arm, a wheel having its maior portion within the peripheral contines of the arm and a marginal portion in registration with the slot and projecting thereabove, a wheel carried by the upper member in cooperative relation to the mst-mentioned wheel. said wheels being arranged for rotation on substantially horizontal and parallel axes lying in a substantially vertical plane that is generally normal to the arm and with their peripheral surfaces in opposing relation, means for urging one wheel in a substantally vertical direction toward the other wheel.

means for moving said one wheel in a reverse direction against the action of the mst-named means, means for imparting continuous rotation l to the wheels in opposite directionasaid wheels being arranged to feed material placed therebetween, and means adapted to be connected to a source of high frequency current for creating a high frequency electric field between the peripheral portions of the wheels, said means in' cured to one end of the-depending member and 14 projecting laterally thereof. an upper member amxed to the bracket and disposedabove the arm in spaced relation thereto, a wheel carried' by the arm proximate the free end thereof, said wheel having its major portion within the peripheral connues. of the arm and a marginal portion in registration with the slot and projectin'g slightly beyond the exterior surface of the arm, a wheel carried by the upper member above the ilrst-named wheel. said wheels being arranged for rotation on substantially horizontal and parallel axes in a substantially vertical plane generally normal to the arm and with their peripheral surfaces in opposing relation. at least the peripheral portion of eachwheel being electrically conductive. means for normally urging one wheel in a substantially vertical direction toward the other wheel, means for moving said one wheel in the opposite direction against the action of the first-named means. means for imparting continuous rotation to the wheels in opposite directions, said wheels being arranged to leed material placed therebetween, andmeans adapted to :be connected to a. source of high frequency current for creating a highl frequency electric neld between the peripheral portions of the wheels, said` means including said wheels.

l NORMAN V. CHRISTENBEN.

HAROLD J. LE VEBCON'I'E. ALBERT M. SCHWEDA.

REFERENCES CITED The following references are of record in the tile of this patent:

OTHER REFERENCES ilzlectr'eme,l August ma, "an Electronic sewing Machine." pp. 91-93, 160,162, 164. les

I0 and188. 

